A grammatical morpheme which inflects onto a stem and cannot stand alone as an individual word. A Bound morpheme is a morpheme that must attach to a word stem. A Free morpheme on the other hand may stand alone as a free word (e.g., the word visit in re-visit is a free morpheme (and hence a word). The re- portion of the word is a prefix and thus bound. A prefix attaches at the beginning of the word, an infix to the middle, and a suffix attaches at the end.

Affixes are word parts that are "fixed to" either the beginnings of words (prefixes) or the ending of words (suffixes). The word disrespectful has two affixes, a prefix (dis-) and a suffix (-ful).